1. Field of the Invention
The present invention pertains generally to an electric motor actuator for a motor vehicle lock for a side door lock, rear door lock, hood lock or the like. More specifically, the present invention is directed to an electric motor actuator for a motor vehicle lock and includes a reversible drive motor and an actuator drive which can be rotary driven by the drive motor. The electric motor actuator further includes an operating lever which is dynamically coupled to the actuator drive for switching the lock into an xe2x80x9cunlockedxe2x80x9d and xe2x80x9clockedxe2x80x9d operating state, an antitheft lever which is spring-loaded with a pretensioning spring and which is dynamically coupled to the actuator drive for holding the operating lever in the xe2x80x9clockedxe2x80x9d operating state. An emergency actuating element is used for manually engaging an antitheft lever into an xe2x80x9cantitheft offxe2x80x9d operating state to overcome a catch element on the actuator drive. The antitheft lever can be switched out of the xe2x80x9cantitheft offxe2x80x9d operating state into an xe2x80x9cantitheftxe2x80x9d operating state through a pretensioning spring on the antitheft lever such that the antitheft lever is held in the xe2x80x9cantitheft offxe2x80x9d operating state by a control crank on the actuator drive, and is held in the xe2x80x9cunlockedxe2x80x9d operating state by the operating lever.
2. Description of the Related Art
German Patent DE 44 33 994 C1 discloses a conventional electric motor actuator for a motor vehicle lock including an actuator element comprising an actuator disk which is driven clockwise and counterclockwise by an electric drive motor, and therefore can be reversibly driven. Other prior art devices of the type mentioned above are disclosed in German Patent DE 33 19 354 C2, U.S. Pat. No. 5,409,277, and Published German Application DE 198 27 751 A1.
These prior art devices, however, fail to disclose a more detailed configuration of a combination including a drive motor and an actuator disk. An electric motor actuator having an actuator disk as the actuator element has proven to be compact and reliable. In one such motor vehicle lock, an actuator disk is regularly used with an actuating lever system and a locking lever system. Generally, the actuating lever system has an outer actuating lever and an inner actuating lever whereby the outer actuating lever is connected to an outside door handle, while the inner actuating lever is connected to an inner door handle. The locking lever system generally has at least one inner locking lever that is either made separately, for example, leading to an inside locking button, or can also be integrated with the inner actuating lever. On the front side doors of a motor vehicle and on the rear door of a station wagon there is also an outer locking lever which is connected to a lock cylinder and/or a remote control means.
The use of a xe2x80x9clocked-antitheftxe2x80x9d operating state means that the motor vehicle lock cannot be opened by undue application of force to the inner locking lever and/or the inner actuating lever. This unallowable application of force is possible after breaking a window, but should remain ineffective in the xe2x80x9clocked-antitheftxe2x80x9d operating state. The locking lever system of the motor vehicle lock is switched back and forth by means of the electric motor actuator between the operating states xe2x80x9cunlockedxe2x80x9d, xe2x80x9clockedxe2x80x9d, and xe2x80x9clocked-antitheftxe2x80x9d. The operating lever of the actuator can be manually switched back and forth between the xe2x80x9cunlockedxe2x80x9d and xe2x80x9clockedxe2x80x9d operating states. If, however, the actuator is in the xe2x80x9clocked-antitheftxe2x80x9d operating state, the operating lever is blocked in the xe2x80x9clockedxe2x80x9d operating state by way of the antitheft lever. If the electric drive motor fails in this operating position, actuation must be produced by way of a mechanical emergency actuating element which engages the antitheft lever, especially a key-actuated outer locking lever of the locking lever system. The antitheft lever with the actuator disk remains unchanged and can be mechanically/manually set back into the xe2x80x9cantitheft-offxe2x80x9d operating state. In this state, the operating lever is released, and can be mechanically/manually switched from the xe2x80x9clockedxe2x80x9d operating state into the xe2x80x9cunlockedxe2x80x9d operating state by actuating the inner locking lever and/or the inner actuating lever.
In the prior art devices, an emergency actuation function is implemented in that the antitheft lever is pretensioned in the xe2x80x9cantitheft offxe2x80x9d operating state by a pretensioning spring or the like, and can be moved by means of a driver projection on the actuator disk into the xe2x80x9cantitheftxe2x80x9d operating state if the operating lever at this time is in the xe2x80x9clockedxe2x80x9d operating state. In addition, driving by means of the actuator disk takes place via a catch which can be raised from the outer locking lever for emergency actuation. The antitheft lever then snaps back into the xe2x80x9cantitheft offxe2x80x9d operating state under the force of the pretensioning spring.
In such electric motor actuators, manual unlocking when the central interlock drive fails can be accomplished easily, reliably and promptly. The construction of the antitheft lever necessary for this purpose with pretensioning springs and a raisable catch is, however, relatively complex in terms of mechanical construction. In addition, when the spring of the pretensioning spring for the antitheft lever breaks, emergency mechanical actuation is no longer possible. The arrangement of the actuator disk, the operating lever and the raisable catch in the above-explained electric motor actuator is such that the catch in the xe2x80x9cantitheftxe2x80x9d operating state must accommodate very high forces under certain circumstances. This high application of force to the catch can only be structurally accomplished with difficulty. Only with very high quality materials which are then correspondingly expensive can this be done. Kinematically, this arrangement has a defect in that the directions of rotation of the actuator disk are not unequivocal for throwing over the operating lever.
Based upon the design having a catch and pretensioning spring on the antitheft lever, it is necessary that the operating lever is thrown over once clockwise, another time counterclockwise into the same operating state, therefore, into a xe2x80x9clockedxe2x80x9d or xe2x80x9cunlockedxe2x80x9d operating state. Which direction of rotation is actually necessary is then determined by the respective position of the catch. Therefore a very intelligent, efficient electronic control is necessary; this again results in major costs.
Accordingly, it is an object of the present invention to overcome the aforementioned disadvantages in improving the design of the conventional electric motor actuator of the initially mentioned type with consideration of the requirements for emergency mechanical actuation.
This object is achieved in an electric motor actuator for a motor vehicle lock having an antitheft lever that is automatically controlled by an actuator drive, and thus not in conjunction with an operating lever. Control of the antitheft lever takes place such that the antitheft lever is pretensioned by means of a pretensioning spring or the like in the direction of an xe2x80x9cantitheftxe2x80x9d operating state, and therefore, can be switched from an xe2x80x9cantitheft offxe2x80x9d operating state into an xe2x80x9cantitheftxe2x80x9d operating state. If the pretensioning spring breaks, the antitheft lever remains either in the xe2x80x9cantitheft offxe2x80x9d operating state or can be manually/mechanically switched into an operating state by means of an emergency actuation mechanism. Moreover, an additional catch is not employed since the antitheft lever can be held by a control crank on the actuator drive or disk in the xe2x80x9cantitheft offxe2x80x9d operating state.
Other advantages are provided due to the elimination of an addition catch, and thereby an additional spring mechanism. In addition, control of the electric motor actuator can be made simple due to the overall construction causes the actuator disk to unambiguously activate the operating lever. Consequently, a single direction of rotation of the actuator disk is always assigned to the displacement of the operating lever into the same operating state. In accordance with an aspect of the present invention, it is, however, advantageous that the desired manner of operation of the actuator be preserved and nevertheless the antitheft function has been integrated into the actuator itself.
Another advantage of the electric motor actuator in accordance to the present invention is also its compact structure which can be especially facilitated by the actuator disk or the like being made in three planes, specifically a middle plane for coupling the actuator disk to the electric drive motor, a lower plane for coupling the actuator disk to the operating lever, and an upper plane for coupling the actuator disk to the antitheft lever. The terms xe2x80x9clowerxe2x80x9d and xe2x80x9cupperxe2x80x9d are interchangeable and in this case according to the preferred teaching are defined such that xe2x80x9clowerxe2x80x9d means the position nearest the bottom of the housing and xe2x80x9cupperxe2x80x9d means the position farthest from the housing bottom.
The present invention will be better understood by those skilled in the art and the above objects will become more apparent in the following detailed description of the preferred embodiment of the invention.